The general field of this invention relates to skin barriers for ostomy or wound drainage use. For this purpose, the compositions are prepared in the form of rings, sheets or blankets, which are fitted around the stoma ostomy opening protecting the skin from the intestinal fluids (ileostomy and colostomy) or urine (urostomy). Ostomy appliances for collecting the discharged fluids may be applied to the outer surface of the skin barriers. To facilitate this attachment, the outer surfaces of the barriers may comprise porous or non-porous films which are laminated to the sheet of the barrier composition, and which usually have their outer surface coated with a pressure-sensitive adhesive, depending on the adhesive properties of the material itself. The present invention is not concerned with such structural details but only with the barrier composition, and particularly with barrier compositions adapted for urostomy and ileostomy use. Ostomy barrier compositions composed of mixtures of elastomers with hydrocolloids are known. See, for example, U.S. Pat. Nos. 3,339,546 and 4,253,460. For this type of barrier composition, the elastomer, which may be a natural or synthetic rubber, or mixtures of such rubber, comprises the continuous phase, and the hydrocolloid is dispersed therein in particulate form. Both natural hydrocolloid gums such as pectin and gelatin and synthetic hydrocolloids such as carboxymethylcellulose have been used in various admixtures. The rubber such as polyisobutylene provides the compositions with an adhesive, dry tack characteristic. The dispersed particles of hydrocolloid absorb water, and also when wet acquire a wet tack adhesive characteristic. Such compositions have been formulated in a wide range of proportions of elastomer to hydrocolloid for use with intestinal ostomies, such as ileostomies and colostomies, and 35 to 45% hydrocolloid. For urostomy use, larger proportions of the elastomer are used, such as 85 to 95% polyisobutylene.
In urostomy applications, the barrier composition is subject to attack by the urine which is discharged through the stoma. At the same time, however, the inner surface of the barrier is in contact with the skin and desirably absorbs the moisture discharged from the skin as perspiration. It is desirable to provide the barrier composition with a moisture absorbing characteristic. However, the inclusion of hydrocolloid which provides the moisture-absorbing characteristic also makes the composition urine-absorbing. The absorbed urine tends to attack and degrade the composition. Further, if too much moisture or urine is absorbed, the hydrocolloid swells undesirably, causing the barrier to pucker and pull away from the skin. This condition can progress until the barrier becomes unusable and must be replaced. For uses such as urostomy and ileostomy, extended mechanical and adhesive endurance of the barrier is important. It may be desired to leave the barrier in place for a week or longer. Therefore, the art has been presented with a difficult problem of formulating barrier compositions of optimum characteristics for urostomy use. Heretofore, no such composition has been provided which is moisture-absorbing while substantially non-swelling, and at the same time provides a high level of resistance to urine and other corrosive fluids such as found with ileostomies.